Document 0qMZxz9L1gMe2BE1wmem26wDV

0007-SWP-00011 *\ i \ QO 2 On ON ON Unfinished P Problem By DR. C. D. HOLLE Director of Paint Rttwarch The Sherwin-Williams Co Detroit* Michigan From a paper read before the Cin Indianapolis Paint &' Varnish Produ 30, 1934. (Official Digest, Federatio ; Varnish Production Clubs, Ma 0007-SWP-000115757 PRODUCTS PIGMENTS, COLORS, CHEMICALS "Oslo" Leaded Zinc Pigment Zinc L*td SO* - 40% I 45% -- 36% / "Permolith" Lithopone - Normal / Blued | Unblued All oil absorptions / Reinforced 50-53% Zinc Sulphide "Permolith" Lithopone .... ^ Tiunited 15% Tloj Pure Zinc Sulphide White Lead........................- Old Dutch 1 Dry Quick Process f Pulped in Linseed Oil Colors, Dry & Pulped in Linseed Oil Chrome Yellows--C. P. snd Reduced Chrome Greens--C. P. snd Reduced Chinese Blue Peru Reds snd Toners Toluidine Reds snd Toners Litharge .......... Red Lead ......... Gloss Makers Color snd Vsrnish Makers ! Insecticide Manufacturers Oil Refiners 70%, 85%. 98%, 95% Pb30, Zinc Sulphate ("Rayon" brand} ( ZnSOs -- SHjO \ ZnSOs -- lHaO Cadmium Metal 99.5+% Pure THE OZARK SMELTING & MINING CO. EXECUTIVE OFFICES: 101 Prospect Are, N. W,, Cleveland, Ohio, U. S. A. MINES: Magdalens. New Mexico SMELTERS: Coffeyville, Kansas 0007-SWP-047U9 WILLS [OZARK; .aska/a. FOREWOR HP HE problems-treated in this p the paint industry, in fact have much discussion. Dr. Holley's trea is based on his wide acquaintance an out the paint and raw material ind bined experience of the laborator Williams Company and allied co these problems from independent an ably no other chemist in the coun proving ground or understanding and applica volved. r, yV ! DR. C. D. HOLLEY Director of Psint Research The Sherwin-Williams Co. Detroit. Michigan , Dr. Holle a consultant ing & Min company fo improvemen Leaded Zin pone have practical e knowledge. No major change has been ma ment processes until thoroughly pro lation, application by practical paint THE OZARK SMELTING 0007-SWP-000115758 Ik 63 M S UNFINISHED PAINT PROBLEMS An address by Dr. C. D. Holley, to llle Ctncinnali-Daylon-/ndtanapolit Paint and Varnish Production Club, May 30th, 1934. Those of us who ore actively concerned with paint formulation find considerable difficulty in keeping our ieet on solid ground A large number of new raw materials continually demand our attention; new lines 01 merchandise are required to fit the ever-changing sales picture; frequent discussions must be held with sales departments on current sales problems All these activities leave us little time to devote to many of our basic paint problems. 1 Several of these' basic problems furnish the ground work for our discussion this evening, and perhaps we can gain the most benefit by con ducting a symposium or "round table discussion," taking as our subiect "Unfinished Paint Problems." Granulation Our first unfinished problem is "Granulation" of mixed paints. The number of. paint manufacturers who say they don't have any "Granulation" is rather amazing. They are sincere in their belief, but your speaker has never seen a'-can of anybody's mixed paint containing ainc oxide, japan drier and a trace of moisture, which would not show an objectionable degree of granulation within a year, providing the paint was kept in a warm place. Aside from objectionable settling or caking in the package, there is nothing which vexes the user of mixed paint more than to open a can : and find it full of granules or "com flakes," which can be eliminated only : by straining at the expense of a considerable wastage of material and loss of time. A tremendous amount of money has been spent by paint manufacturers to insdl confidence as to the desirability of using mixed paint. Unless we do a better job than we have done, we cannot blame the customer if he returns to the use of white lead in oil. We know what granulation is, via.; the formation of zinc soaps oi limited solubility, which in turn are deposited from a supersaturated solu tion in the oil, resulting either In small granules throughout the paint, or by slow growth develop into large "com flakes" on .the surface of the paste portion. We know that in order for granulation to develop in linseed oil paints, there must he present line oxide, driers and moisture. These items are present in all white and tinted mixed points. Therefore, granulation will take place in all such paints if they are allowed to stand for a sufficient length of time. ' Our problem is to retard the rate of granulation so ms to insure usage of the paint before granulation has progressed to an objectionable degree. This is accomplished by eliminating as far as possible, those agencies which promote it. _ Unfortunately, the most active agent we have to contend with is elevated temperatures and this condition is beyond our control. Granula tion proceeds about five times as rapidlv at 100* F. as at 70* F. Your speaker has examined cans stored for only a year in Florida and southern Texas which had granulated as badly as in five years storage north of the Ohio River. The use of add refined oil strongly accelerates granulation. The higher the add value the more rapid the granulation. On the other hand, alkali refined oils, because of their freedom from oil adds, are very effective-in retarding granulation. The character and quantity of drier used ha drier, arc strong motors of granulation Liiin and low m manganese and cubail arc among tho mental Unfortunately the use of hnoleate uner the paint in the can. and sales departments which ness usually pay the penalty of excessive granu oi light colored rosin driers. Rather stroi { claims have been made that th container through the closure, due to changes in tric pressure, is a big factor In causing granula for their basis the well known fact that the line s linseed oil are less soluble and, therefore, precip Our investigations show that while the volum and the type ot friction closure have a distinct nevertheless if the other important factors whic present, viz.; elevated temperatures, acid refine little moisture, and the usual type of lead-fre excessive granulation will take place in a vacuu sealed container Turpentine and turpentine driers have littl factors are present which promote rapid granula ceeds quite slowly, turpentine, through its greate soaps, is of benefit in delaying the appearance of If the oils and driers exert a marked influen tion, we would expect that the type of zinc o produce equally important differences, and this taining substantial percentages of excessivel granulate rapidly. . On the other hand, the high leaded zinc types, because of the intimate association of same partide, and because of the absence of exc retarding influence on granulation. Other conditions being equal, we find that leaded zinc, the rate of granulation is only one equivalent mechanical mixture of lead-free z is used. The following tables indicate comparative like conditions with a conventional pigment c zinc oxide and Titanox. Effect of Vehicle Composition on Composition uii Refined (AV 2.7) Refined (AV 2.7) Refined (AV 0.3) Refined (AV 2.7) Refined (AV 2.7) Refined (AV 3.0) Refined (AV 4.0) Refined (AV 4.0) Refined (AV 27) Raw (AV 2.9) Raw (AV 2.9) * Drier increased 100%. Drier Rosin Free Absent Rosin Free Rosin Free Rosin Free* Rosin Rosin Free Rosin Naphthenic type Rosin Free Rosm 0007-SWP-000115759 Leaded Zinc vs. Mechanical Mixtures of White Lead and Zinc Oxide Pigment Mechanical Mixture 25/65 Leaded Zinc Mechanical Mixture 3S/6S Leaded Zinc Composition Oil Raw Raw Refined (AV 3.0) Refined (AV 3.0) Comparative Rate Drier of Granulation Rosin Rosin Rosin Rosin Free Free 3H 2 7Jd 3 i Therefore, if we are to retard the rate of granulation in our mixed paints to a point where it will not be noticeable .even with a slow sales turnover, we should use: ' 1. An oil having an acid value as close to ietto as possible. 2. The minimum amount of rosin-free drier, 3. An approved grade of 33/65 leaded zinc. Checking vs. Chaikins A second unfinished problem of major Importance is the proper balance between Checking and Chalking in extenor paints. We arc all familiar with the difficulties we encounter when we try to arrive at this balance. If we increase the zinc^oxide content sufficiently to eliminate Chalking we encounter severe Checking and Cracking. If we increase the Lead or admixture of Lead and Titanium Pigments to a point where objectionable Checking and Cracking disappear, we find our paints Chalking to an undesirable extent This situation is easily understood by reierring to the accompanying chart. I C"Zine Oxid* FVtoMitT A$ ffrchwcal Mixture "1 E D*7nc Olds Introduced Throw** LoodMAlCf These graphs represent in a broad way. performance of the different pigment combinat over a thrcc-ycar exposure period For simp arc included with white lead The curve marked "A" represents the che ance of ordinary zinc oxide with white lead or and titanium pigments. At 25% zinc oxide is "slight,at 35% "considerable," and 42% "ba Curve "C" indicates the chalking tendenc It is "slight" with 40% zinc oxide, ''consider about 20%. At 33% zinc oxide content we have de with the same paint. Our problem is, obviously, to reduce tendencies of the zinc oxide, so we can use m the region of "slight*' chalking with practical Our own organization has attacked this the high leaded zinc oxides m which die eliminated This type of pigment has a ver checking and cracking compared with mecha composition. Graphs "B" representing the checking, acteristics of leaded zinc show that zinc oxid increased without encountering checking trou chalking is reduced. With a mechanical mix of ordinary zinc oxide wc have slight ch whereas with leaded zinc we may have ne reaching the `Might" checking phase, and th terially lessened, becoming intermediate b siderable " If we can elevate the chalking curve s the checking tendencies, we could move in position where we could use upwards of 35% 50% or leaded zinc, and have a mild degree very satisfactory from both a durability and From our exposure studies this procedu the use of relatively small percentages of p terially delays the initial chalking and retard first eighteen months of exposure. High Hiding Power P On other occasions your speaker has disc with the use of titanium and zme sulphide pig Today we find the users of titanium groups. First, those using a moderate perc titanium-barium pigment. Second, those u centages of 35% to 50%. Third, those usin 10% to 12%--with a moderate percentage of Because of the many features involved, dearly shown which of these three groupings ever, one feature is very evident. As the p pigment, or titanium oxide plus inert pigmen zinc oxide can be introduced into the paint difficult to produce a paint having balanced durability. t , Gur exposure tests show consistently t this situation is through the use of a high lute we found a mechanical mixture of white lead arid ordinaly zinc i ufcidc, to give as satisfactory durability with the titanium pigment* as is obtained^ when replaced with a similar content of an approved leaded zinc. I The use of leaded zinc plus a percentage oi heat processed tong o*l ' to retard chalking appears to have solved our major problems in the use ' of titanium pigment# in outside whites. We hare, however, a definite i and increasing demand for better tint retention of our light colors, and . the use of zinc sulphide has been suggested as a means of improving this situation. _ Our further experience with pure zinc sulphide as a paint pigment for exterior usage is encouraging. As would be expected, it has behavior characteristics of its own, which must be learned and definitely recognized if %ve are to formulate with it successfully. If we avoid the use of acid refined oils and rosin driers, use 35/65 leaded zinc as the source of zinc oxide, and eliminate basic carbonate white lead in favor of basic lead sulphate, we can expect very satisfactory durability and improve our tint retention. Just why the presence of basic carbonate white lead in zinc sulphide paint* should cause earlv and excessive checking and cracking, and that replacement with basic lead sulphate overcomes this trouble, is difficult to understand. It is, however, evident from our exposure studies, that the limiting factors with zinc sulphide formulations are quite different from tho<e of the titanium pigment paints. Usage of Soybean Oil \ fourth unfinished problem is the satisfactory use of soybean oil and other oils of the semi-drying type. The domestic soybean industry is one of the young giants in the commercial field which is demanding attention with increasing insistence. The rate of growth has been amazing but is easily understandable when viewed from the effect of tariff enactments. Today there is a very strong economic trend towards a much larger domestic soybean industry with increasing insistence by agricultural inter ests that a substantial percentage of soybean oil be used in place of linseed oil from imported flax seed in our various paint products.' Their argument, which is entirely logical, is--"if we buy your paints you should buy our oil" . . If we are to use a substantial percentage of soybean oil in manufactur ing our paint products, our natural inclination is to inquire what can be done to improve the drying qualities of thia oiL Assuming that the iodine value is an approximate measure of the drying value, other conditions being equal, an interesting investigation was conducted at the University of Wisconsin, beginning in 1912 and extending over an eight year period m an effort to raise the iodine value by selective breeding. Starring with the beans from a single plant, the oil of which had an iodine value of 132, a crop was obtained having a high of 133 and low of 108. These were used as the starting points for breeding oils of high and low iodine values. For seven successive years the beans from the plant having the highest iodine value in the high line were selected for .planting, ana a like treatment followed (Or the low line. . . *4 The results obtained by the University of Wisconsin investigators GO shown on (he following chart indidates 'first, that improvement in the drying quality of soybean oil is not likely to come through the usual process of selective .breeding, and second that climatic variations produce definite effects on the'iodine value. - , ', . ... ... a This investigation resulted in the prod from a chemical standpoint; one having t values from the tall late maturing plants, a ably lower analyses, from the early dwarf in maturity of fourteen days between the tw Taking the five-year period during wh definitely established, the averages of the respectively for the high value and low val Investigators inform us that the oil co by a transformation of the accumulated ca time for the formation of the unsaturated iodine values is at a point very late in th just preceding full maturity. Cool weath value as it permits the plant to pass th formation under conditions which favo highly unsaturated glycerides. ' 3I l 0007-SWP-000115760 0007-SWP-000115761 , An increase to an average iodine value of 1-10 would appreciably .improve the drying qualities or soybean oil It may be doubtful, however, it this can be brought about, asit appears that an average of 135 to 1J6 is about the physiological limit ot the soybean plant. There remains one other possibility. If two soybean varieties could be found having fairly high iodine values but in wnich the iodine value is determined by different genetic factors, there is the possibility oi isolat ing a superior type from a hydrid between them. This would involve so much work and so many chemical analyses that soybean investigators have hesitated to undertake this problem. It appears, however, that there are other factors which can affect the drying of soybean oil besides iodine value. We know that freshly pressed linseed oil contains anti-oxidant substances which slow down the rate of the oil very appreciably. These anti-oxidant bodies or "footy" material are partially removed by aging the oil and the drying rate is thereby considerably improved. ' . Raw soybean oil also contains a considerable quantity of these anti oxidant bodies, the proportions of which vary, and they are apparently much more difficult to remove by aginp than in linseed oil This explains why different lots of raw soybean oil having similar iodine values arc frequently different in their drying qualities when incorporated into paints. If we are to use maximum quantities of soybean oil in paints it may be necessary to use a partially refined soybean oil, in which the anti oxidant bodies have been partially removed by a treatment considerably less expensive than the usual alkali refining process. If in order to obtain paints having the best all around performance, we find it necessary to use a mixture of pigments, it would be logical to expect that the best soybean oil paints would contain a mixture of oils This appears to be the case, and we have found that a mixture of 8 parti linseed oil, 4 pans soybean oil and 1 part processed tung oil, dries about as well as linseed alone. Doubtless other equally Satisfactory oil mixtures are in current use Our exposure studies with soybean oil paints reveal some interesting features, we find that at least a week of excellent drying weather should intervene between coats, if we are to prevent early checking and cracking 'of the top coats, due to their greater rate of contraction or shrinkage I through more rapid oxidation, t This tendency to check and crack is materially reduced if a refined soybean oil is used, i. --one in which the "break" containing the anti oxidant bodies has been definitely removed. Paints containing up to 2$% soybean oil (vehicle basis) which has its drying qualities property balanced by a mixed oil combination, when used with leaded line, white lead and titanium pigment mixtures, dries similarly to a straight linseed oil paint and, as far as we can determine, with equal durability. t Because of the tremendous variations in the drying of different deliv eries ot raw soybean oils--which appears to be largely eliminated if partially refined--it would seem that it soybean oil is to oe used on a large scale by the paint industry, the oil producers will have partially to refine their oil to remove anti-oxidant bodies and sell the resulting oil at nearly 4a the raw oil price. , Another interesting development is safflower oil. Nearly every paint manufacturer in the country has received letters promoting this new crop. and it the farm organizations act hack o: ihi> the production of a considerable gaSlonage ot It vw!l h .<sll worth our while to k*e| in stations ui the northwest which arc doing saitlovser. Actually about 300 acres were see sufficient seed available to plant 2000 acre* this The success of (his movement depends First--acceptance by the stock and dairy intere concentrated feeding material, comparable to co and second--adequate tariff protection, particul already a large grower of safflower Saffiowc*- oil having an iodine value of 14 ve-v fair drying qualities, if 10% of processe exposure tests arc not sufficiently advanced to However, our experience with soybean oil pai indicate that the slower drying ods g*ve disti leaded nnc than with ordinary zinc oxide in Lithopone Points Our final "Unfinished Problem*' for di>cuss pamt Th,$ is a familiar subject to most of u very brief The particular point we wish to considerable portion of the consuming public price for a paint of great durability, there is of the public who are today* very economical purchasing paint Wc n> paint manufacturers hairn't done in meeting this situation Wc have the sem discussed, available at very economical pric lithopone, a pigment ot great hiding powe Through the use of these economical raw ma meet this demand for an economically priced The large lithopone manufacturers includ done a most excellent job m perfecting th exposure studies of these companies have al improvments in lithopone paint formulation next few years continues at the present rap ashamed of the quality of our lithopone paint field The situation becomes much more simp requirements for repaint work are different Very good results are now obtainable,on rep value of a special priming coat, particularly has been demonstrated by l?r. Browne of the These priming coats appear to be especially lithopone paints. To date our best results have been obtain of a 40/60 leaded zinc, and 15% inert pigm avoid the use of acid refined oils and rosm moderate percentage of semi-drying oil, if centage of tung oil, has not been found to a if adequate drying time is allowed between co